Air register



Jan. 9, 1934.

J. MCDONALD ET AL 1,943fi83 AIR REGISTER 3 Sheets-Sheet 1 Filed May 18, 1952 INVENTORS Jammy fi flanazid BY 66a]:

ATTO R N EY Jam 3 3934. J. MCDONALD El AL 3343,1383

AIR REGISTER Filed May 18, 1952 3 Sheets-Sheet 2 INVENTORS James 117 Domain Jim. 9, 1934 J. MCDONALD El AL.

AIR REGISTER Filed May 18, 1932 3 Sheets-Sheet 3 Patented Jan. 9, 1934 UNITED STATES AIR REGISTER James McDonald, Wechawken, N. J., and George B. Dahl, Richmond Hill, N. Y., assignors to Todd Dry Dock, Engineering & Repair Corporation, New York, N. Y., a corporation of New York Application May 18, 1932. Serial No. 612,010

Claims.

This invention relates to oil burning furnaces, and our improvement is directed to means within the air registers for controlling the centrifugal motion of the air supply as it passes therethrough 5 for delivery to the furnace, to thereby concentrate the air supply mainly in the region of the flame zone, thus promoting economy and'efliciency in fuel oil consumption.

It is known in this art that the air coming from a pressure source to support combustion in an oil burning furnace, due to the relative position and characteristics of the supply source, is caused to whirl in its passage through the air register and the whirling motion thus set up is it maintained in the flow of, air entering the furnace, with the result that the air thus introduced m tates and enters the furnace with an increased velocity at its outer diameter, asit passes through the restricted circular opening to the furnace.

m This whirling motion of the entering air produces a variable vortex in the flame centre, causing the flame to back on thebumer and pulsate, with the consequent overheating of the burner parts, thus increasing the temperature of the incoming oil and further accentuating the liability to pulsate and cause damage to the boiler hreeching and plates.

James McDonald, in his Patent No. 1,710,370, dated April 23, 1929, stated the conditions above noted, and provided longitudinally straight, centrally directed vanes, extending from the circular, air ported wall of the register, for the purpose of checking the circulatory motion of the air entering the furnace, and directing the air forwardly.

In our present invention, however, we provide a series of specially shaped vanes, which are suitably located in the register "with relation to the air ports, and have the effect of giving more of a centripetal motion to the flowing air that is guided by the co-acting vane surfaces, which cause the currents of air to swiri intimately around the atomized oil with a minimum of rl dispersion.

Actually the thus whirling flow of air hugs closely the axis of the atomized oil, and becomes completely associated with the fuel, the condition thus provided being most favorable to combostion; whereas, without the use of our vanes, the centrifugal forces set up by rotation of the air currents in the register, cause the whirling flow of air to more closely hug the perimeter of the venturi as the whirling stream widens out in outering the furnace, thereby creating a partial vacuum at the flow centre, which has to be satisfied by a back rush of flame that tends to (Cl. 158-15) v overheat the burner and name cone, also resulting in pulsation and the production of smoke through imperfect combustion.

Other features and advantages of vention will hereinafter appear.

In the drawings:

Figure 1 is a front elevation of an air register.

Fig. 24is a horizontal section thereof, taken on the line 22 of Fig. 1.

Fig. 3 is a vertical section, 3-3 of Fig. 1. I

Fig. 4 is a vertical front section, taken on the line 4-4 of' Fig. 3. I

Fig. 5 is a side sectional view of a furnace and air register, with diagrammatic indications. of 20 the air flow course resulting from the use of our novel vanes.

Fig. 6 is a similar view, with diagrammatic indications of the air flow ;course when our novel vanes are not used, and} Fig. 7 is a perspective view of a vane.

The representation in'the drawings is that of a Todd type burner and air register, the furnace being such as may be used to serve a Scotch marine boiler.

The general organism of the air register includes the forward plate 1 in the form of a hinged our intak'e n on the line door, and an annular wall 2 provided with ports 3, said wall 2 having an inwardly extending flange 4 that is opposed to the plate 1, and said l:=;l e as forming a. seat for the radial flange 5 of a Venturi ring 6, which projects into the furnace entrance 7.

A ported air ring 8 is shown as disposed revolubly within the wall 2, said ring 8 having means whereby it may be rotated to regulate the on admission of air that flows theretoin the manner known in the art as the Howden draft.

The elements thus far described form no part of our invention but are included herein-as an example of an air register with which our im-- provement is applicable. As is well known in this art air may be supplied from a suitable source to the interior oi the air register upon a boiler and is, dircctedthereinto by means of an air casing such as that indicated ate.

Also, as is well known, air enters the register tangentially, causing the air streams to whirl therein, and the rotating eilect thus provided continues in the air flow as it issues fro the venturi, with the deleterious efiects set forth in 105 the fore part of this specification.

We aim to cure these ill efiects and to control the direction of the inflowing air streams for entcient service by means of blades or vanes of novel shape and surface contours. These vanes, indilid cated generally at 10, present concavo-convex surfaces, a series thereof being herein shown as positioned within the register and equally spaced therefrom to modify ,the flow path of the air streams that enter the register through the admission ports, said vanes imparting a whirling motion to the air streams passing through the register.

As shown these vanes each have a root portion 11 that lies against the inner peripheral boundary of the register, the vane continuing from said portion, through an obtuse bend 12, into a right-angle triangular portion 13 that is concavo-convex both in cross-section and longitudinal section, thus providing a dished effect.

Also said vane has a lateral wall 14 at one side which is adapted to lie against the rearwardboundary of the register, said wall 14 being here I shown provided with means for its attachment to the Venturi flange 5, the attaching means being represented for example by a slot 15 in the wall 14 to receive a bolt 16 that penetrates the flange 5 and is secured in the flange 4 of register wall 2.

-' Obviously other means of attaching the vanes may be employed.

The vanes of the series are all curved alike, and they are arranged in overlapping relation, that is, the forward portion, or apex 17 of each vane lies in the same radius as the root of an adjacent vane, but, because the vanes are curved inwardly from their root portions 11, therefore adjacent vanes are spaced apart and provide a passageway for theflow of air streams that enter the register through the admission ports.

, The admitted air streams, it will be seen, flow over the convex outer surfaces of the vanes and against the concaved inner surfaces of adjacent succeeding vanes, whereby said streams which have entered through the admission ports with centrifugal effect, are accorded a more or less centripetal effect as they whirl about the, centrally disposed burner tube 18 and flame cone 19, and this centripetal motion is continued in the flowing air streams as they issue into the furnace through the venturi 6.

With the aid of an anemometer within a furnace we have tested the air velocities therein both when. the register has been equipped with our new vanes-and without, and the results of these tests are diagrammatically expressed respectively in Figs. 5 and 6. Thus, in Fig. 5, with the air ports one half open, and four of our improved vanes in place, flow of air is shown, by arrows, passing tangentially through the venturi opening. The short arrows show currents of air flowing out in front of the burner tip for a certain distance, the whirling currents of air, with their centripetal tendency, hugging closely to the axial centre of the atomized oil, thereby forming a restricted flame zone of high intensity, in which quicker and more complete combustion is obtained in the front portion of the furnace.

In comparison, similar tests made without the use of our improved vanes (see Fig. 6), show the whirling currents of air hugging closely to the perimeter of the venturi under centrifugal impulse, and flowing away from the fuel axial centre within the furnace, forming a vortex and leaving a central cavity of partial rarefaction, that induces the return currents to flow axially toward the burner, thereby tending to set up a back firing condition that has'heretofore proved so difficult to overcome in oil burning furnaces.

Variations within the spirit and scope of our invention are equally comprehended by the foregoing disclosure.

We claim:--

1. The combination with a liquid fuel burning furnace including an air register having a cylindrical wall provided with a plurality of ports,

a ported control ring to co-operate with said 30 ports, andjan axially disposed fuel atomizing burner, of a series of dished vanes mounted in fixed relation to said ports in said register and curved inwardly toward said burner, so as to impart a centripetal eflect to air streams 35 whirling through said register.

2. The combination with a liquidfuel buming furnace including an air register having a cylindrical wall provided with a plurality of ports, a ported control ring to co-operate with 00 said ports, and an axially disposed fuel atomizing burner, of a series of air-flow vanes mounted in fixed relation to said ports in said register and inclined inwardly toward said burner, said vanes each having a right-angular, triangular portion that is concaved at its inner surface, so as to impart a centripetal effect to air streams whirling through the register.

3. The combination with a liquid fuel burning furnace including an air register having a cylindrical wall provided with a plurality of ports,

a ported control ring to co-operate with said ports, and an axially disposed fuel atomizing burner, of a plurality of air-flow directing vanes equally spaced from said register, said vanes 5 having root portions by which they are mounted in fixed angular relation to said ports, said vanes being arranged in overlapping relation and having inwardly curved concavo-convex portions that co-act to form passageways for air streams no admitted through the ports, and the concaved surfaces of said vanes serving to impart a centripetal effect to the passing streams of air.

4. The combination with a liquid fuel burning furnace including an air register having a cyn5 lindrical wall provided with a plurality of ports,

a portedcontrol ring 'to co-operate with said ports, and an axially disposed fuel atomizing burner, of a plurality of air-flow directing vanes equally spaced from said register, said vanes having root portions by which they are mounted in flxed angular relation to said ports, said vanes-having right-angular, triangular portions, continuing from said root portions that are concavo-convex both in cross-section and longitudinal section, adjacent vanes co-acting to form passageways for air streams admitted through the ports, and the concaved surfaces of said vanes facing inwardly so as to impart a centripetaleffect to the passing streams of air.

5. The combination with a liquid fuel burning furnace including an air register having a cylindrical wall provided with a plurality of ports,

a ported control ring to co-operate with said ports, and an axially disposed fuel atomizing, burner, of a plurality of air-flow directing vanes equally spaced from said register, said vanes having root portions by which they are mounted in-flxed angular relation to said ports, said vanes having right-angle, triangular portions continuing from said root portions that are concavo-convex both in cross-section and longitudinal section, the root portion of each vane overlapping the apical portion of a preceding vane, adjacent vanes co-acting to form passageways for air streams admitted through the ports, and the concaved surfaces of said vanes facing inwardly so as to impart a centripetal effect to the passing streams of air.

- JAMES McDONALD.

GEO. B. DAHL. 

